Database / Mnesia basics Interview questions
What are dirty operations in Mnesia?
Dirty operations (mnesia:dirty_read/1, mnesia:dirty_write/1,
mnesia:dirty_delete/1, and similar) perform a single read or write directly against the table,
bypassing transaction locking and the coordination needed to keep replicated copies perfectly in sync during
the operation.
mnesia:dirty_write(#person{id = 1, name = "Ada", age = 34}), mnesia:dirty_read({person, 1}).
They're significantly faster than their transactional counterparts precisely because they skip that coordination, which makes them a reasonable choice for high-throughput, low-consistency-requirement workloads (a hit counter, a cache-like table) where an occasional inconsistency during a concurrent update or a node failure mid-write is tolerable. They're the wrong choice whenever an operation depends on multiple related writes succeeding together, since dirty operations offer no atomicity across more than one call.
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